The Planted Tank Forum - View Single Post - KH Standard / How to
View Single Post
post #15 of (permalink) Old 08-27-2010, 10:18 PM
Darkblade48's Avatar
Join Date: Jan 2008
Location: Toronto/Singapore
Posts: 10,716
As KevinC mentioned, you can easily increase your precision by increasing the volume of water to be tested.

The gH and kH test kits work on the basis of titration. As KevinC also mentioned, if your 4 dkH reference solution is slightly off (i.e. 4.1 dkH), then it will require that 5th drop to change the colour to a bright yellow.

As for where your error is coming from, I would suspect the sodium bicarbonate as well. Despite it being a brand new box, it is not completely air tight, and there are surely impurities left over from the manufacturing process, etc. However, since it is going to go into a drop checker, which is not the most precise tool anyway, you can probably get away with the reference solution you already have made up.


A Primer to Pressurized CO2 and A Primer to Planted Tanks
Eheim Pimp #362 - Eheim 2213 x2, Eheim 2028, Eheim 2217, Eheim surface skimmer and Eheim autofeeder.
Victor Pimp #33 - HPT272-125-350-4M
Darkblade48 is offline  
For the best viewing experience please update your browser to Google Chrome